Summery Summery

Authenticate a message. Uses symmetric-key cryptography.

Syntax Syntax

ParagonIE_Sodium_Compat::crypto_auth( string $message, string $key )

Description Description

Algorithm: HMAC-SHA512-256. Which is HMAC-SHA-512 truncated to 256 bits. Not to be confused with HMAC-SHA-512/256 which would use the SHA-512/256 hash function (uses different initial parameters but still truncates to 256 bits to sidestep length-extension attacks).

Parameters Parameters


(Required) Message to be authenticated


(Required) Symmetric authentication key

Return Return

(string) Message authentication code

Source Source

File: wp-includes/sodium_compat/src/Compat.php

    public static function crypto_auth($message, $key)
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AUTH_KEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_AUTH_KEYBYTES long.');

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_auth($message, $key);
        if (self::use_fallback('crypto_auth')) {
            return (string) call_user_func('\\Sodium\\crypto_auth', $message, $key);
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::auth($message, $key);
        return ParagonIE_Sodium_Crypto::auth($message, $key);



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